1. Field of the Invention
The invention relates to a heat dissipation component for a light-emitting diode.
It also relates to a lighting and/or signalling device equipped with a heat dissipation component and to a method for manufacturing a device of this type.
The technical field of the invention is, generally, that of headlamps, signalling and/or lighting components for motor vehicles, comprising at least one light-emitting diode, in particular what is known as a “power” light-emitting diode.
2. Description of the Related Art
The prior art has already proposed the use of a light-emitting diode on account of the numerous advantages that it has.
Indeed, the diode consumes less electrical power, even at the same light flux intensity, than a discharge or incandescent lamp traditionally used in the motor vehicle field.
The diode does not radiate omnidirectionally but rather radiates in a more directional manner than the discharge lamp. Thus, the amount of light, and therefore electrical power, lost is less.
However, during its operation, the diode produces heat. Heating of the diode is detrimental to orderly operation thereof, as the higher the temperature of the diode rises, the more its light flux decreases.
In order to lower its operating temperature, the diode comprises a metal heat dissipation base, often referred to as a “slug”, allowing thermal contact to be established with a heat dissipater, such as a heatsink, in order to dissipate the heat produced by the diode.
Numerous components allowing the heat of a light-emitting diode to be dissipated are known.
Document EP-A-1 463 391, in the name of the Applicant, relates to a method and a component of the same type. However, the method for fixing the base of the diode to the heat dissipater is necessarily carried out by an expensive welding process, laser spot welding.
The present invention seeks, in particular, to provide a solution allowing use to be made of other fixing methods, such as fusion welding in a furnace, despite the fragility of components such as the light-emitting diode.
Document EP-A-1 139 019 describes a heat dissipation component associated with a power light-emitting diode, of which each of the two electrical connection tabs is electrically connected to a track of a printed circuit board.
The printed circuit board extends above a copper heat dissipater, forming a vacuum between the printed circuit board and the heat dissipater.
The printed circuit board comprises a through-hole in which the diode is arranged, so that the heat dissipation base of the diode establishes thermal contact with the copper heat dissipater.
A heat conduction agent is arranged between the heat dissipation base of the diode and the heat dissipater in order to improve the heat conduction between the base of the diode and the heat dissipater.
A dissipater of this type allows the heat produced by the diode to be discharged effectively but does not allow precise orientation of the diode.
Indeed, the base of the diode is arranged on a heat conduction agent of the thermal grease, thermal paste, thermal adhesive type, which is therefore not solid. Accordingly, the heat conduction agent used is not a reference surface allowing the diode to be oriented in a precise manner.
Similarly, the tabs for fixing the diode that fix the diode to the printed circuit board do not provide a reliable positioning reference in view, in particular, of their flexibility.
However, in the case of a lighting and/or signalling device, the relative position of the light beam emitted by the diode in relation to an optical element, such as a light reflector and/or a lens, has to be precise if optimum output of the lighting and/or signalling device is to be obtained.
Moreover, the design of the dissipation component described in document EP-A-1 139 019 does not allow a flexible printed circuit board, known as a flexboard, to be used, given that the diode is fixed to the printed circuit board and that a vacuum separates the printed circuit board from the heat dissipater. This aspect is a drawback, in particular if the printed circuit board is to be arranged in various planes.